Electropneumatic brake.



W. v. TURNER.

ELECTROPNEUMATIC BRAKE.

APPLICATION FILED AUG-Z6, 1912- LWE UW; I Patented A r. 20, 1915..

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W. V. TURNER.

-ELECTRQPNEUMATIC BRAKE.

APPLICATION FILED AUG.26, 1912.

Patented Apr. 20, 1915.

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MAGNET RELEASE PIPES; 2's canrsgk.

WITNESSES INVENTOR W. V. TURNER.

ELECTROPNEUMATIC BRAKE. fi-wmfifiwmfigm. APPLICATION map AUG-26, 1912.Patented APR 20, 1915.

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WITNESSES INVENTOR W. V. TURNER.

ELEGTROPNEUMATlC BRAKE.

APPLICATION FILED AUG.26. 1912.

Patented Apr. 20, 1915.

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wire earn-e WALTER V. TURNER, OF EDGEWOOD, PENNSYLVANIA, ASSIGNOR TO THEWESTING- HOUSE AIR, BRAKE COMPANY, OF WILMERJDING, PENNSYLVANIA, ACORPORATION OF EENNSYLVANIA.

ELECTROPNE'UMATIC BRAKE.

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Specification of Letters Patent.

Patented Apr. 2%, T315;

Application filed August 26, 1912. Serial No. 716,963.

an improved electro-pneumatic control valve mechanism in which thepressure in an application chamber controls the supply of fluid to andfrom the brake cylinder.

Another object of my invention is to provide means for holding theapplication valve mechanism in emergency position regardless of thebrake cylinder pressure.

Another object of my invention is to provide means controlled by theapplication valve mechanism for supplying fluid to the brake cylinder toeffect an emergency high pressure application of the brakes.

Another object of my invention is to provide an application valvemechanism having two positions, one for efi'ecting a service applicationof the brakes, and the other for effecting an emergency application ofthe brakes.

Still another object of my invention consists in providing a brakecontrolling valve mechanism having an application chamber and inwhich-the equalizin pressure ma be adjusted to suit the class 0? servicein W ich the same is. employed.

Other objects and advantages of the invention' will appear in the moredetailed description of the invention hereafter set forth.

In the accompanying drawings; Figure 1 is a diagrammatic view of anelectro-pneumatic brake apparatus embodying my improvements as appliedto two cars; Fig. 2 a schematic diagram of the electric wiring circuits;Fig. 3 a central sectional diagrammatic view of the electro-pneumaticcontrol valve showing the parts in normal release position; Fig. 4 asimilar view, showing the parts in electric service applicationposipassage 42.

. tion; Fig. 5 a similar view, showing the parts in electric emergencyapplication position; Fig. 6 a sectional view of the graduated releasecap in position for cutting out the graduated release; and Fig. 7 asectional View of the equalizing piston cap in the position forconnecting in the additional application chamber.

As shown in Figs. 3 to 5, the electropneumatic control valve device maycomprise an application valve mechanism 1, equalizing valve mechanism 2,quick action valve mechanism 3, emergency valve mechanism 4, emergencyswitch portion 5, protection valve device 6, high pressure emergencyvalve mechanism 7, electric release magnet 8, electric service magnet 9,and electric emergency magnet 10. p The application valve mechanism 1comprises a piston 11 dividing the piston chamber into two chambers 12and 13, the cham- .ber 12 being in communication with a passage 14leading to an application chamber 15. The piston 11 operates anapplication valve 16 contained in valve chamber 17 which is connected bya pipe 18 to the main reservoir pipe line 19-. Said piston also controlsa release valve 20 contained in valve chamber 21 which is connected tothe brake cylinder through a passage 22 leading to passage 23. Containedin piston chamber 24. and mounted on the piston stem 25 of the piston 11is a piston '26 adapted to separate the piston chamber 13 from the valvechamber 21.

The equalizing valve mechanism 2 comprises a piston 2 contained inpiston chamber 28 which is connected through passage 29, chamber30, andpassage 31 with the train pipe 32 and operates a main slide valve 33 andgraduating slide valve 34 both contained in valve chamber 35 which isconnected by a passage 36 with a pressure chamber 37. The quick actionvalve mechanism 3 comprises a piston 38 dividing the piston chamber intotwo chambers 39 and 40, the chamber 39 being connected to a passage 41and chamber 40 to an atmospheric exhaust Said piston operates a quickaction valve 43 contained in valve chamber 30 and is adapted to controlcommunication from train pipe passage 31 to exhaust passage 42. Theemergency valve mechanism 4 comprises a piston 44 contained inpistonchamber 44 which is connected to a passage 45 and said pistonoperates a valve 46 contained invalve chamber 47 which is connected toquick action chamber 48 through a passage 49. The emergency switchportion ,5 comprises a piston 50 contained in piston chamber 51 which isconnected to passage 41 and said piston operates an electric switch 52which controls the circuit of the emergency magnet 10. The protectionvalve device 6 comprises a piston having the chamber 53 at one sideconnected to a passage 54 leading to chamber 30 and having its oppositeface open to an exhaust port 55. The

. high pressure emergency valve mechanism 7 comprises a piston providedwith a valve seat 56 on oneside controlling communication from a passage57 leading to the main reservoir valve chamber 17 to brake cylinderpassage 23. The chamber at the opposite face of the piston 7 isconnected to a paspressor 69.

sage 58 which leads to the seat of the application valve 16. Theelectric release magnet 8 operates a release valve 59 which con- .trolscommunication from a passage 60 leading to the seat of the equalizingslide valve 33 to an exhaust. port 61. The electric service valve 9operates valve 62 for controlling communication from train pipe passage45 to passage 63 leading to brake cylinder passage 23. The emergencymagnet 10 operates a valve 64 for controlling communication from trainpipe passage 65 to an exhaust ort 66.

As shown in Fig. 1 of the rawings, the car air brake equipment maycomprise an electro-pneu'matic brake valve 67 at each end of the car andconnected to the train pipe 32 and the main reservoir pipe line 19.

The main reservoir line is connected to a main reservoir 68 adapted tobe charged .to the pressure carried by means of a com- On cars notprovided witha compressor and main reservoir a storage reservoir 70 maybe provided in place of the main reservoir. The electro-pneumaticcontrol valve 71 is connected by pipe 72 as one or more brake cylinders73.

For controlling the brakes electrically, the brake valve 67 is providedwith contacts connected to supply train wire 74, service applicationWire 75, release wire 76, emergency' Wire 77, and positive battery wire78 is connected to supply wire 74. A negative battery wire 7 9 is alsoprovided and a source of current 80 is connected across the positive andnegative battery wires. The brake valve has the following positions;release, lap,

service and emergency, and these positions are the same for bothelectric and pneumatic control.

In operation, when the train pipe 32 is charged With fluid underpressure, air flows from passage 31, chamber 30 and passage 29 89, andpassage 90. Air is also free to flow through port 91 in main slide valve33, passage 92, cavity 93 in cap 89 and passage 94 to pipe 95connectingwith a supplemental reservoir 96 and through ports 97 and 98to a resistance increasing cavity 99 in the slide valve 33.

The size of passages through which the supplemental reservoir is chargedis so proportioned with respect to the feed groove 86 that the time ofcharging is the same whether the supplemental reservoir is cut in orout, the increased fiow of air due to the added volume of thesupplemental reservoir being provided by means of the additional flowthrough the passages 87, 88, and 90 directly from the train pipe to thepressure chamber. It should also be understood that fluid is supplied tothe train pipe by means of the brake valve at a sufiicient rate toprovide the additional fluid required when the supplemental reservoir iscut in.

Fluid from the train pipe also flows from chamber 30 through passage 54to the face of the protection valve 6 and when the train pipe pressureattains a predetermined degree, the protection valve is quickly shiftedto its outer position, owing to the exposure of the full area of theprotection valve 'to train pipe pressure as soon as the same lifts fromits seat, the opposite side of the valve being constantly open toatmospheric pressure. The protection valve being open, air flows fromthe train pipe through port 100 and passage 45 to piston chamber 44,forcing the emergency piston 44 to release posi tion, as shown in F ig.3. The valve chamber 47 is then charged through feed gr0ove 101 and thequick action chamber 48 is also charged through passage 49. In thisposition, passage 41 connects piston chamber 51 with the quick actionpiston chamber 39 and these chambers are maintained at atmosphericpressure through port 102 in piston 38, which connects chamber 39 withchamber40, open to quick action exhaust passage 42; so that leakage intothe chambers 51 and 39 can escape and thus prevent the possibleunseating of the quick actionvalve 43 and the closing of the emergencyswitch 52.

Main reservoir air is contained in the chamber 17 and flows thencethrough port 103 and passage 58 to the spring side of the high pressureemergency valve 7. Main reservoir air also flows through passage 57 tothe chamber at the opposite side of the valve 7 but as a portion of thearea of the valve is open to the brake cylinder passage 23, the

high pressure emergency valve 7 is held ,to its seat with the assistanceof spring'l04c.

If it is desired to effect an electric service application of thebrakes, the brake valve handle is turned to service applicationposition, which is also pneumatic service application position, and theelectric circuit of the service magnet 9 is closed, so that said magnetis energized and the valve 62 is opened, as shown in Fig. 4. The releasemagnet circuit is also closed, so that the release magnet 8 is energizedand the release valve 59 thereby closed. Fluid is thereupon vented fromthe train pipe passage 31, chamber 30, passage 54, port 100,passage 45,cavity 105 in cap 106, passage 107, and passage 63 to the brake cylinderpassage 23.

Passage 63 is of such size as to limit the reduction is train piperessure to a rate insufficiently rapid to e ect the movement of theemergency piston 44, since the feed groove 101 is large enough to permita corresponding reduction in the pressure in quick action chamber 48,but the rate of reduction is rapid enough to insure the movement of theequalizing piston 27 to its outer position.

The first or initial movement of the equalizing piston toward serviceapplication position closes the feed groove 86, the additional chargingport 87, and the release port 108, opens service port 109, and cavity110 in graduating valve 3-1 connects ports 98 and 111, thus exposing thearea of the friction increasing cavity 99 to atmospheric pressure, so asto increase the differential of pressure required to move the equalizingslide valve to service application position.

While the electric release valve 59 is closed in making a serviceapplication of the brakes, the passage is still at atmospheric pressureand since the volume of this passage is very large as compared with thevolume of the resistance increasing cavity 99, the effect of connectingsaid cavity with the passage 60 upon the preliminary movement of thegraduating slide valve 34: is to subject said cavity to substantiallyatmospheric pressure.

One object of the above provision for increasing the frictionalresistance of the valve is to reduce the sensitiveness of the equalizingvalve sufficiently to prevent movement tending to cause an applicationof the brakes upon unintentional fluctuations in train pipe pressure dueto variations in feed valve action or other causes. Another object is toobviate diiiiculty in releasing the brakes due to inability to secure asufiicient differential on the equalizing piston, as might be the casewhere the brakes can be applied on a very small train pipe reduction.

Further movement of the equalizing piston 27 shifts the main slide valve33 to service application position, in which communication isestablished from valve chamber 35through port 109 and passage M to aptlt plication chamber 15 and also application cylinder 12. Port 109remains open until the pressure in the pressure chamber 37 has beenreduced to a degree slightly less than that in the train pipe, when theequalizing piston 27 and graduating valve 31 are shifted so as to closethe port 109. Fluid supplied to the application cylinder 12 causes themovement of application piston 11 to close the brake cylinder exhaustport 112 through the movement of release valve 20 and connect port 113in application valve 16 with chamber 21. Air from the main reservoir isthus permitted to flow to the brake cylinder from chamber 21 throughpassages 22 and 23. Valve chamber 21 is connected to chamber 13 by meansof a feed groove 111 around piston 26, in service application position,so that the pressures in said chambers are maintained equal in serviceapplications.

Flow of air from the main reservoir to the brake cylinder continuesuntil the pressure in the brake cylinder is substantially equal to thepressure in the application cylinder' 12, when the graduating spring 115shifts ehe application valve mechanism to service The pressures onopposite sides of the pisbe any loss of pressure on either side of thepiston the same will be moved toward the lower pressure, thus causingeither a slight increase or a reduction in the pressure in chamber 21and the brake cylinder. The service application magnet ma either be heldenergized, to hold the app ication valve 16 open and permit fullequalization of train pipe and brake cylinder pressures, or the same maybe energized for a few seconds only to cause a partial application ofthe brakes.

If it is desired to release the brakes, the brake valve handle is movedto release position, in which the release magnet circuit is open, sothat the release magnet 8 is deenergized and the release valve 59 isopened. The train pipe port in the brake valve is also open so as torestore the train pipe pressure to normal. The equalizing piston 27 isforced to release position by the increase in train pipe pressure and itshould be noted that first movement of the piston 27 toward releaseposition causes port 97 to register with port 98 so that fluid from thepressure chamber flows into the resistance increasing cavity 99, and thearea of this cavity being thus balanced the resistance of the valve tomovement is reduced, and consequently the equalizing valve mechanism isadapted to release at a lower differential than is required to effect anapplication of the brakes. I K

In release position of the equalizing valve position, closing theapplication port ton 11 are now balanced but if there should mechanism,-the application chamber 15 and application cylinder 12 are connected tothe exhaust through passage 14, port 108, cavity 110, port 111, andpassage 60. The pressure on piston 11 being released, the piston isshifted to release position inwhich fluid in the brake cylinder isreleased through the cavity 105, and passage 65.

The reduction in train pipe pressure causes the equalizing piston toshift to emergency position, which is the same as service applicationposition. The protection valve device 6 is also shifted outwardly,closing the train pipe passage 54 and opening communication from passage45 through a port 116 to the atmospheric port 55. The pressure inchamber 44 is thus quickly reduced and the emergency piston is shiftedto emergency position in which the slide valve 46 uncovers a port 117leading to passage 41. Fluid is then supplied from the quick actionchamber 48 to the switch piston 50 and also to the quick action piston38, thus I causing the train pipe vent valve 43 to open and vent airfrom the train pipe and the emergency switch 52 to close, so as toinsure the closing of the circuit of the emergency magnets 10. The quickaction valve mechanismand the emergency switch remain in emergencyposition until the quick action chamber 48 drains to the atmospherethrough the small port 102 in the quick action piston 38, then the quickaction valve mechanism and the switch mechanism are returned to normalposition by their respec tive springs. Chamber 13 is also connected tothe. atmosphere through passage 118, cavity 119 in slide valve 33,passage 120, cavity 121 in emergency valve 46, and exhaust port 122. I I

With fluid from the pressure chamber flow-ing to the applicationcylinder 12 and fluid in chamber 13 vented to the atmosphere, theapplication piston is quickly shifted to its extreme position in whichthe seal 123 is seated and the groove 114 is closed. In this position,port 113 opens communication for supplying main reservoir air from valvechamber 17 to the valve chamber 21 and the brake cylinder as in serviceapplications, and in addition, passage 58 lead-. ing to one side of thehigh pressure emergency valve 7 is connected to the atmosphere throughcavity 124 in valve 16 and passage 125. As main reservoir pressure is onthe opposite side of the valve 7, the same is shifted to open a largedirect opening from the main reservoir supply passage 57 to the brakecylinder passage 23. With chamber 13 open to the atmosphere, the area ofthe piston exposed to the pressure of the application cylinder isconsiderably greater than the area exposed to the pressure in chamber 21and consequently the full main reservoir pressure may be retained in thebrake cylinder if desired, although the full equalized pressure in theapplication cylinder may be much less than the main reservoir pressure.

In releasing the brakes after an emergency application, upon increasingthe train pipe'pressure, the protection valve 6 is first shifted torelease position and then fluid is admitted from the train pipe tochamber 44, so as to shift the emergency piston 44 to release position.Further increase in train pipe pressure shifts the equalizing piston 27to release position, which in turn effects the movement of theapplication piston to release position. The opposing pressures on thehigh pressure emergency piston are then balanced by the admission ofmain reservoir air through port 103 and passage 58 to the spring side ofsame, so that the spring 104 causes the seating thereof in normalposition.

The release of the brakes may be graduated electrically by moving thebrake valve handle between electric release and electric lap positions.The train pipe is charged in the release position, so that theequalizing piston 27 is shifted to release position, but the releasemagnet valve 59 is first opened when the brake valve is-moved to releaseposition and then closed when the brake valve is moved to lap position,so that the pressure in the application cylinder is reduced a few poundsat each graduation. As will be understood from the description ofoperation previously given, the application piston is moved to open thebrake cylinder exhaust and release air from the brake cylinder until thebrake cylinder pressure substantially equals the reduced applicationcylinder pressure. Further graduations in brake cylinder pressure may bemade in the same manner.

In case the electrical features of the control valve become inoperativefrom any cause, the brakes will be operated pneumatically by variationsin train pipe pressure through the usual movements of the brake valve,the positions of the brake valve being the same for both electric andpneumatic operation.

Provision is made for pneumatic graduated release by providing asupplemental lease position of the equalizing valve mech-. anism, theincrease in pressure in the valve chamber 35 thus produced then operatesto .to remain in service application position,

the brakes would first be applied in service until the brake cylinderpressure attained the equalizing pressure and then upon reduction intrain pipe pressure-below that of the protection valve spring 126, theprotection valve 6 is shifted to emergency position, thus causing fluidto be vented from the emergency piston 44, so that the same is shiftedto emergency position to cause an emergency application of the brakes asheretofore described. a

While the control valve is designed more particularly fortractionservice, the same may also be employed in steam rpad service,but as the basis upon which the braking power is calculated is usuallydifferent for steam roads, means are provided for reducing thisdifference to a minimum. For example, the usual basis for braking powerin steam road service is 90% on 60 pounds brake cylinder pressure, whilethe service for which the control .valve is normally de-- signed, 100%on pounds brake cylinder pressure is employed.

In order to eliminate this diflerence in braking power as much aspossible, an additional application chamber 127 is provided, which whendesired may be connected to the usual application chamber 15 byadjusting the equalizing piston cap 128 so that a cavity 129 thereinconnects passage 130 leading to application chamber passage 14 withpassage 131 leading to the additional application chamber 127, as shownin lFi 7.

luid from the pressure chamber therefore equalizes into the extra volumeprovided by the additional appllcation chamber in making a serviceapplication otthe brakes, so that the equalizing pressure is reduced. Inservice, where no main reservolr line is provided, the reservoir mustbe" charged from the train pipe and for th s purpose, a port 132 isprovided whlch is open to the train pipe only in the release position ofthe equalizing p1ston27 and in the steam road position of the equal z ngcap 128, a cavity 133 therein contaming check valve 134 connects port132 with passage 135 opening into. the valve chamber 17. Thiscommunication for charging the main reservoir is restricted so that thesamecannot take air from the train pipe at a rate suificient to eflectthe usual braking operations.

Having now described my invention, What I claim as new and desire tosecure by Letters Patent, is

1. In a fluid pressure brake, the combination with an application valvedevice having a differential piston subject to the op posing pressuresof an application chamber and the brake cylinder, for controlling theadmission of fluid to the brake cylinder and an automatic valve devicesubject to variations in train pipe pressure for controlling thepressurein said application chamber, of an emergency valve mechanism operatingupon a sudden reduction in train pipe pressure for effecting anemergency application of the brakes and a passage-way controlled by themovement of both the automatic valve device and the emergency valvemechanism to emergency position for venting fluid from one side of saiddiflerentialpiston to assist in holding the application valve device inemergency position.

2. In a fluid pressure brake, the combination with an applicationchamber, an application valve device comprising a valve for supplyingfluid to the brake cylinder, a differential piston having one headsubject to the pressure of an application chamber and the other headsubject to brake cylinder pressure, and. an equalizing port around thesecond head for normally equalizing the fluid pressures on oppositesides thereof, and an automatic valve device operated by variations intrain pipe pressure for controlling the pressure in sa1d applicationchamber, of an emergency valve mechanism operating upon a suddenreduction in train pipe pressure for efl'ecting an emergency applicationof the brakes and a passageway controlled by the movement of theautomatic valve device and the emergency valve mechanism to emergencyposition for venting fluid from the brake cylinder side of saiddifl'erential piston to' thereby assist in holding the application valvedevice in emergency position.

' 3. In a fluid pressure brake, the combination with an applicationchamber and a valve device operated by the pressure in the applicationchamber for supplying fluid to the brake cylinder, of a valve mechanismcontrolled by said application valve device for venting fluid from asource of pressure said application valve device for normally supplyingfluid to one side of said valve mechanism, said application valve devicebeing adapted in emergency position to connect said portto theatmosphere.

' 5. In a fluid pressure brake, the combination with an applicationchamber and a valve device operated by the pressure in the applicationchamber for supplying fluid to the brake cylinder, of an automatic valvedevic'e subject to the opposing pressures of the train pipe and apressure chamber for controlling the admission of fluid from thepressure chamber to the application chamber and an additionalapplication chamber adapted to be connected to the regular applicationchamber.

6. In a fluid pressure brake, the combination with an applicationchamber, a valve mechanism operated by the pressure in said applicationchamber for efiecting an application of the brakes, and an automaticvalve device operated upon a reduction in train pipe pressure forsupplying fluid to said application chamber, of electrically controlledmeans for eflecting a reduction in train pipe pressure and forcontrolling the exhaust of fluid from said application chamber.

7. Ina fluid pressure brake, the combination with a brake cylinder, ofan application chamber, a valve mechanism comprising a piston subject tothe opposing pressures of the brake cylinder and said applicationchamber and avalve carried by said piston for supplying fluid to thebrake cylinder to eflect a service application of the brakes in oneposition and for supplying fluid to effect an emergency pplication ofthe brakes in another position.

8. In a fluid pressure brake, the combination with a brake cylinder, ofan application chamber, a valve mechanism comprising a piston subject tothe opposing pressures of the brake cylinder and said applicationchamber and a slide valve carried by said piston for supplying fluid tothe brake cylinder to eflect a service application of the brakes upon agradual reduction in train pipe pressure in one position and forefi'ecting an emergency application of the brakes upon a suddenreduction in train pipe pres sure in another'position.

9. In a fluid ressure brake, the.combina. tion with a bra e cylinder, atrain pipe, an application chamber, a valve mechanism .operated by thepressure in the application chamber for supplying'fluid to the brakecylinder in one position, and an automatic valve device operating upon areduction in train pi e ressure for supplying fluid to the applicationchamber, of means operating upon a sudden reduction in train pipepressure for shifting said valve mechanism to another position forefl'ecting an emergency application of the brakes.

10. In a fluid pressurebrake, the combination with a brake cylinder, atrain pipe, an application chamber, a valve mechanism operated by thepressure in the application chamber for supplying fluid to the brakecylinder in one position, and an automatic valve device operating upon areduction in train pipe pressure for supplying fluid to the applicationchamber, of an emergency valve device for supplying fluid to the brakecylinder in an emergency application of the brakes and means operatingupon a sudden reduction in train pipe pressure for shifting saidapplication valve mechanism to'another position for effecting theoperation of said emergency valve device.

11. In a fluid pressure brake, the combination with a brake cylinder,train pipe, 'an application chamber, a valve mechanism operated by thepressure in the application chamber for supplying fluid to the brakecylinder in one position, and an automatic valve device operating upon areduction in train pipe pressure for supplying fluid to the applicationchamber, of an emergency valve device for supplying fluid to the brakecylinder in an emergency application of the brakes, means operating upona sudden reduction in train pipe pressure for shifting said applicationvalve mechanism to another position for eflectin the operation of saidemergency valve device, and electrically controlled means for eflectinga sudden reduction in train pipe pressure.

12. In a fluid pressure brake, the combination with a brake cylinder, atrain pipe, an application chamber, a valve mechanism operated by thepressure in the application chamber for supplying fluid to the brakecylinder, and an automatic valve device operating upon a reduction intrain pipe pressure for supplying fluid to the application chamber, ofmeans operating upon a sudden reduction in train pipe pressure forefiecting an emergency application of the brakes and electricallycontrolled means for effecting a gradual reduction in train pipepressure and a sudden reduction in train pipe pressure.

13. In a fluid pressure brake, the combination with a brake cylinder, atrain pipe, an application chamber, a valve mechanism operated by thepressure in' the application chamber for supplying fluid to the brakecylinder, and an automatic valve device operating upon. a reduction intrain ipe pressure for'supplying fluid to the app ication chamber, ofmeans operating upon .a sudden reductionin train pipe pressure foreffecting an emergency application of the brakes, an electricallycontrolled valve-for efiecting a gradual reduction in train pipe niaaoeapressure, and an electrically controlled valve for efl'ecting a suddenreduction in train pipe pressure.

14. In a fluid pressure brake, the combination with a brake cylinder, atrain pipe, an application chamber, a valve mechanism operated by anincrease in pressure in the application chamber for supplying fluid tothe brake cylinder in one position, and an automatic valve deviceoperating upon a reduction in train pipe pressure for supplying fluid tothe application chamber, of an emergency valve mechanism operating upona sudden reduction in train pipe pressure'for eflecting the movement ofsaid application valve mechanism to another position and means operatedby said valve mechanism in the last mentioned position for supplyingfluid to, the brake cylinder with increased pressure.

15. In a fluid pressure brake, the combination with a brake cylinder, atrain pipe, an application chamber, a valve mechanism opera'ttedby anincrease in pressure in the application chamber for supplying fluid tothe brake cylinderin one'position,,and an automatic valve device adaptedupon a gradual reduction in train pipe pressure to make full traverseand open communication for supplying fluid to the application chamber toeflect the movement of the application valve mechanism to one positionfor effecting a service application of the brakes, of a separate valvemechanism operating upon a sudden reduction in train pipe pressure toeflect the movement of said application valve mechanism to anotherposition in which an' emergency application of the brakes is eflected.

In testimony whereof l have hereunto set my hand.

WALTER V. TURNER.

Witnesses A. M. CLEMENTS, B. A. U.

